Bermudagrass rhizome initiation and longevity under differing potassium nutritional levels
Titel:
Bermudagrass rhizome initiation and longevity under differing potassium nutritional levels
Auteur:
Keisling, T. C.
Verschenen in:
Communications in soil science and plant analysis
Paginering:
Jaargang 11 (1980) nr. 6 pagina's 629-635
Jaar:
1980
Inhoud:
The influence of K nutritional level on 'Coastal bermudagrass' (Cynodon dactylon L. Pers.) rhizome characteristics under field conditions was recently reported. As K nutritional stress increased, the weight of rhizomes found growing beneath the sward were found to decrease drastically. Additionally spring regrowth was shown to be proportional to the amount of rhizomes present in the fall. Obviously, K nutritional stress resulted in the deterioration of the rhizomes already present and possibly on the initiation of new rhizomes and their subsequent growth or on both of these factors. A greenhouse study was conducted to investigate the effect of K nutritional status on the initiation of new rhizomes. Darco (Grossarenic Paleudult; loamy, siliceous, thermic) soil from a K deficient area was collected for the study. Potassium rates of 0, 33.6, 67.3, 101, 135 and 269 kg/ha was applied to each of four pots. Eight rhizome pieces 2.5 cm long (containing a node in the middle) were placed 2.5 cm below the soil surface. Plants were allowed to grow for about eight months. At that time the plants were harvested and the aerial portions analyzed for K while the new rhizomes initiated were counted. An old P X K rate study located on Darco soil with 'Coastcross I' bermudagrass (a culti-var that produces essentially no rhizomes) were observed to determine the longevity of rhizomes under K nutritional stress. Treatments consisted of a 3 X 3 complete factorial of P and K rates. Annual P rates were 0, 68 and 136 kg/ha and K rates were 0, 112 and 224 kg/ha. Measurements consisted of noting whether or not a comparable stand persisted at the 1977 growth season. The initiation of new rhizomes by Coastal bermudagrass was found to be directly proportional to K nutritional stress as measured by tissue concentration. Stand loss of Coastcross I bermudagrass indicated that K nutritional stress results in accelerated below ground stem (rhizome) degeneration.
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